In a session that brought out the mischief in some Republicans, a House committee yesterday began formal action on President Carter's civil service reform bill by greatly expanding and strengthening the protections the bill gibes to federal workers who "blow the whistle" on their bosses.

The House version strays even further from the administration position on that issue than the changes made recently on the Senate side over strenuous administration objections, sources said.

Republicans did most of the talking in support of Carter's proposals yesterday while the Democrats, as expected, revealed considerable disagreement with the president's position and with each other.

Some lobbyists and committee sources complained that the session was slowed by "nit-picking" procedural wranging and what one called "playing to the galleries" by Democrats with large federal employe comstituencies.

With ill-disguised glee, Republicans, led by Edward J. Derwinski (Ill.) poked fun at the Democrats' "amendments to their own amendments" to the president's proposals. The Republicans contrasted the Democrats' tortured camp with their own agreeable "responsiveness" to the president.

At one point, the Republicans carried a 10-to-9 vote in favor of letting administration officials who were present comment on a whistle-blower amendment, and then sat back and watched the committee approve the amendment despite the Carter team's stated objections.

Any amendment introduced by Derwinski was really an administration amendment, which the Democrats had refused to support, according to one Democratic committee source.

"The administration's real friends are the Democrats who disagree on the merits (of the bill) but who are not trying to embarrass the administration" the way the republicans are, the source maintained, adding that probabaly any such administration amendments will be rejected.

The whistle-blowe amendment, written by Patricia Schroeder (D-Colo.), Benjamin Gilman (R-N.Y.), William Lehman (D-Fla.) and James Hanley (D-N.Y.), among other things expands protections against reprisals (such as firing) to employes who charge their agencies with waste or mismanagement, rather than limiting protections to charges involving outright illegalities.

But an amendment added by Hanley to that amendment also requires agencies to investigate employes' charges within a certain time and issue reports on them, with review by a special counsel set up to represent such employes.